Astir and At work

Astir adjective - Marked by much life, movement, or activity.

At work and astir are semantically related In some cases you can use "At work" instead an adjective "Astir".

At work adjective - On the job.

Astir and at work are semantically related in active topic. Sometimes you can use "Astir" instead an adjective phrase "At work", if it concerns topics such as having movement.